Two-Component System Response Regulator ompR Regulates Mussel Settlement through Exopolysaccharides

Abstract

The outer membrane protein (OMP) is a kind of biofilm matrix component that widely exists in Gram-negative bacteria. However, the mechanism of OMP involved in the settlement of molluscs is still unclear. In this study, the mussel Mytilus coruscus was selected as a model to explore the function of ompR, a two-component system response regulator, on Pseudoalteromonas marina biofilm-forming capacity and the mussel settlement. The motility of the ΔompR strain was increased, the biofilm-forming capacity was decreased, and the inducing activity of the ΔompR biofilms in plantigrades decreased significantly (p < 0.05). The extracellular α-polysaccharide and β-polysaccharide of the ΔompR strain decreased by 57.27% and 62.63%, respectively. The inactivation of the ompR gene decreased the ompW gene expression and had no impact on envZ expression or c-di-GMP levels. Adding recombinant OmpW protein caused the recovery of biofilm-inducing activities, accompanied by the upregulation of exopolysaccharides. The findings deepen the understanding of the regulatory mechanism of bacterial two-component systems and the settlement of benthic animals.

Biodeterioration and Chemical Corrosion of Concrete in the Marine Environment: Too Complex for Prediction

“…On the other hand, the EPS-containing biofilm is a stable environment for microbial cells, enabling them to remain active and attached to the concrete surface and minimizing the loss of corrosive metabolites [65]. There is considerable information on EPS, including their make-up, production, and effects [61,[66][67][68][69][70][71], and this will not be further detailed here. Their production plays a part in the development of a complex biofilm, which eventually leads to the adherence of higher organisms, the readily visible "marine biofouling", sometimes called "hard fouling" because of the presence of shell-bearing animals such as barnacles and oysters; this final stage in the marine fouling process is not within the remit of the current article.…”